Outbreak Of Scrub Typhus Research Articles

Scrub typhus outbreak during the Battles of Imphal and Kohima, 1944–45

Scrub typhus outbreak during the Battles of Imphal and Kohima, 1944–45

Scrub Typhus Outbreak among Soldiers in Coastal Training Area, Australia, 2022.

A scrub typhus outbreak occurred among 24 soldiers from 2 Australian Defence Force infantry units following separate training events conducted in the same coastal location in tropical North Queensland, Australia, in June 2022. Seven soldiers visited a hospital, 5 requiring admission. Outbreak recognition was hampered by the geographic dispersion of soldiers after the exercise and delayed case identification resulting from such factors as prolonged incubation, cross-reactive serologic responses to other pathogens, the nonspecific symptoms of scrub typhus, and the illness's nonnotifiable status in the state of Queensland. Our investigation focused on personal protective measures in a subanalysis of 41 soldiers, revealing an association between scrub typhus infection and the use of doxycycline chemoprophylaxis and permethrin uniform dipping.

Spatiotemporal heterogeneity and long-term impact of meteorological, environmental, and socio-economic factors on scrub typhus in China from 2006 to 2018.

Large-scale outbreaks of scrub typhus combined with its emergence in new areas as a vector-borne rickettsiosis highlight the ongoing neglect of this disease. This study aims to explore the long-term changes and regional leading factors of scrub typhus in China, with the goal of providing valuable insights for disease prevention and control. This study utilized a Bayesian space-time hierarchical model (BSTHM) to examine the spatiotemporal heterogeneity of scrub typhus and analyze the relationship between environmental factors and scrub typhus in southern and northern China from 2006 to 2018. Additionally, a GeoDetector model was employed to assess the predominant influences of geographical and socioeconomic factors in both regions. Scrub typhus exhibits a seasonal pattern, typically occurring during the summer and autumn months (June to November), with a peak in October. Geographically, the high-risk regions, or hot spots, are concentrated in the south, while the low-risk regions, or cold spots, are located in the north. Moreover, the distribution of scrub typhus is influenced by environment and socio-economic factors. In the north and south, the dominant factors are the monthly normalized vegetation index (NDVI) and temperature. An increase in NDVI per interquartile range (IQR) leads to a 7.580% decrease in scrub typhus risk in northern China, and a 19.180% increase in the southern. Similarly, of 1 IQR increase in temperature reduces the risk of scrub typhus by 10.720% in the north but increases it by 15.800% in the south. In terms of geographical and socio-economic factors, illiteracy rate and altitude are the key determinants in the respective areas, with q-values of 0.844 and 0.882. These results indicated that appropriate climate, environment, and social conditions would increase the risk of scrub typhus. This study provided helpful suggestions and a basis for reasonably allocating resources and controlling the occurrence of scrub typhus.

Scrub typhus in Northeast India: epidemiology, clinical presentations, and diagnostic approaches.

Scrub typhus is one of the most neglected tropical diseases, a leading cause of acute undifferentiated febrile illness in areas of the 'tsutsugamushi triangle', diagnosed frequently in South Asian countries. The bacteria Orientia tsutsugamushi is the causative agent of the disease, which enters the human body through the bite of trombiculid mites (also known as chiggers) of the genus Leptotrombidium deliense. Diagnosis of the disease is challenging, as its early symptoms mimic other febrile illnesses like dengue, influenza and corona viruses. Lack of rapid, reliable and cost-effective diagnostic methods further complicates the identification process. Northeast India, a mountainous region with a predominantly rural tribal population, has witnessed a resurgence of scrub typhus cases in recent years. Various ecological factors, including rodent populations, habitat characteristics and climatic conditions, influence its prevalence. Entomological investigations have confirmed the abundance of vector mites, highlighting the importance of understanding their distribution and the probability of transmission of scrub typhus in the region. Proper diagnosis, awareness campaigns and behavioural interventions are essential for controlling scrub typhus outbreaks and reducing its impact on public health in Northeast India. Further research and community-based studies are necessary to accurately assess the disease burden and implement effective prevention strategies.

AN OUTBREAK OF SCRUB TYPHUS IN A REMOTE VILLAGE-AN OVERVIEW

Objective: An outbreak of scrub typhus was declared by Public Health authorities in our district in October, 2022. To investigate this a team of experts from Microbiology, SPM, Medicine and Pediatric Medicine was sent to the place of outbreak and they observed that there was heavy vegetation, stagnant water, dwellings heavily infested with rodent population. There was heavy rain in the past two weeks in the district. To investigate the cause of sudden upsurge of febrile illness cases.
 Methods: Blood samples were collected from 28 persons who were symptomatic with fever/headache/diarrhea/rash and myalgia to do tests for Scrub typhus, Typhoid fever, Malaria, Dengue, Complete blood count, CRP, LFT and KFT. The samples which were positive for Scrub typhus in rapid test kits were subjected for IgM ELISA to confirm scrub typhus.
 Results: Seven of twenty-eight patients tested positive for scrub typhus by rapid test (25%), and four of them were positive by IgM ELISA (14.28%). Three patients were Widal-positive (10.7%). More than half samples showed increased CRP levels (53.57%). Thrombocytopenia and mild leucocytosis was observed in scrub typhus cases (42.85%) as well as in typhoid cases.
 Conclusion: Any outbreak during monsoon should be investigated thoroughly not only for the specified disease but also for all infectious diseases that are prevalent in that area.

Notes from the Field: Scrub Typhus Outbreak - Los Lagos Region, Chile, January-February 2023.

Notes from the Field: Scrub Typhus Outbreak - Los Lagos Region, Chile, January-February 2023.

Outbreak of scrub typhus in western part of India: containment and lessons learnt

Background: Scrub typhus is one of the most covert diseases of present era. Diagnosis is often missed, and tools for confirming diagnosis are often not available in resource-poor setups. The aim of the study was to investigate an outbreak investigation and suggests methods of containment. Methods: An epidemiological investigation of Scrub typhus outbreak though active and passive surveillance. Time, Place and person distribution, mean, median stand deviation were used during analysis. Results: Cases presented with high grade fever (100%), bodyache (91%) and headache (81%). Nearly, 22% cases presented with Eschar, 16% of blood samples were positive for OX-19 antigens, 9% blood samples were sent for enzyme linked immunosorbent assay (ELISA) and were positive for IgM antibodies. Conclusions: An outbreak of Scrub Typhus infection was successfully contained without any mortality by effectively using Chemoprophylaxis, judicial use of chemicals and personal protective measures.

A potential tool for predicting epidemic trends and outbreaks of scrub typhus based on Internet search big data analysis in Yunnan Province, China.

Scrub typhus, caused by Orientia tsutsugamushi, is a neglected tropical disease. The southern part of China is considered an important epidemic and conserved area of scrub typhus. Although a surveillance system has been established, the surveillance of scrub typhus is typically delayed or incomplete and cannot predict trends in morbidity. Internet search data intuitively expose the public's attention to certain diseases when used in the public health area, thus reflecting the prevalence of the diseases. In this study, based on the Internet search big data and historical scrub typhus incidence data in Yunnan Province of China, the autoregressive integrated moving average (ARIMA) model and ARIMA with external variables (ARIMAX) model were constructed and compared to predict the scrub typhus incidence. The results showed that the ARIMAX model produced a better outcome than the ARIMA model evaluated by various indexes and comparisons with the actual data. The study demonstrates that Internet search big data can enhance the traditional surveillance system in monitoring and predicting the prevalence of scrub typhus and provides a potential tool for monitoring epidemic trends of scrub typhus and early warning of its outbreaks.

SCRUB TYPHUS DISEASE OUTBREAK AT CHEURAL VILLAGE, LAWNGTLAI DISTRICT, MIZORAM, NORTH-EAST INDIA

Scrub typhus, which is one of the rickettsial diseases, is an acute, febrile illness in men caused by the pathogen, 18 a gram-negative bacterium Orientia tsutsugamushi from the bite of infected mite. Outbreaks of scrub typhus have been reported from various parts of North, South, and Eastern India. There was a report of two unfortunate death cases from Cheural village due to scrub typhus at Lawngtlai district hospital. While, multiple cases, having symptoms like scrub typhus illness were also reported by health officials of the residents of Cheural village, Lawngtlai District, Mizoram. Among the 242 person tested, 80 (33.05%) person were found reactive with Weil felix PROGEN OXK at 1:160 titre value. Maximum numbers of cases were observed among the working age group 20-60 years. Among the different occupational groups, farmers were the most affected as more than 90% of the villagers were involved in forest farming. The five captured rodents’ sera were also tested with Weil felix. All of the captured rodent sera were reactive with one or more antigen. Mites (chigger) were also collected from the rodent samples and the chigger index was found to be 19.2. This study indicated that scrub typhus and other rickettsial diseases were responsible for the outbreak. The extremely high chigger index with reactivity rate reactivity rate of Weil felix with sera of captured rodents strongly indicated the household transmission of scrub typhus and other rickettsial diseases in the outbreak village.

Epidemiological Aspects of Tsutsugamushi Disease (Scrub Typhus) Outbreaks in Republic of Korea and Japan

Epidemiological Aspects of Tsutsugamushi Disease (Scrub Typhus) Outbreaks in Republic of Korea and Japan

An epidemiological outbreak of scrub typhus caused by Orientia tsutsugamushi – A comprehensive review

An epidemiological outbreak of scrub typhus caused by Orientia tsutsugamushi – A comprehensive review

Scrub typhus outbreak in rural area of Purba Medinipur district, West Bengal, India in 2021

Background: Scrub typhus is a reemerging zoonotic disease with no definite preventive measures. Mild to severe clinical manifestation of scrub typhus are occurring in tropical countries. We conducted investigation to confirm the outbreak and vector survey to ascertain transmission of scrub typhus.Methods: A cross sectional study was conducted in Sahid Matangini block of Purba Medinipur district, West Bengal, India between November’ 2020 and January’ 2021. All suspected scrub typhus cases were included for investigation. Environmental and vector survey was also conducted in affected villages.Results: Among total 71 cases, 51 cases were tested for scrub typhus and positivity rate was 13.72% (7/51). Positivity rate was higher in women 9.80% (5/51) than men. Cases found in adult women in the age group of 19-45 years were 35.21% (25/71) and in the children below the age of 15 years were 23.94% (17/71). All the patients developed fever followed by headache, myalgia, cough, rash & eschar. Outbreak started in November’ 2020 and maximum cases were found in December’ 2020. Dumping of household waste inside house was 93%, agriculture fields close to residential houses were 80% and pet animals in household were 69% of total case patients. Trap positivity was 37.5% (3/8) and after examination in laboratory ectoparasites such as adult mites were identified.Conclusions: This was an outbreak of scrub typhus. Mites were found in peri-domestic areas. Household waste is to be dumped away from the residential houses. A clean and vegetation free household environment with proper washing of feet and hand may decrease the risk of scrub typhus.

Is Delhi an Emerging Scrub Typhus Hotspot? An Entomological and Zoonotic Exploration of a Scrub Typhus Outbreak

Background: Scrub typhus is an emerging public health challenge in India with increasing evidence of its activity being reported from all over the country. An outbreak of scrub typhus was reported from an area of South West Delhi, India hitherto not known for scrub typhus activity which prompted this zoonotic and entomological investigation.Methods: Zoonotic and entomological investigations were undertaken in five residential areas of South West Delhi, India located in the vicinity of the reporting hospital to determine the rodent hosts, vector mite diversity, and rickettsial activity in rodents. The rickettsial activity was ascertained using Weil-Felix test.Results: Palam area of Delhi, India is a hotspot of scrub typhus with evidence of tick and endemic typhus activity as well. This study reports the presence of known vectors of scrub typhus viz. Leptotrombidium deliense and Schoengastiella ligula, besides enriching the database of mite fauna of Delhi with an addition of a total of five new records, three of Leptotrombidium - vietzi, bhattipadense, fulmentum, and two records of Ascoschoengastia indica and Walchia lupella.Conclusion: The study reports Delhi as a scrub typhus hotspot. In Delhi, Palam was the most affected and had the highest number of cases and deaths, presence of the vectors of scrub typhus and evidence of tick and endemic typhus activity amongst rodents. The mite database of Delhi has been updated with the addition of five new trombiculid mite records.

Forecasting Scrub Typhus Cases in Eight High-Risk Counties in China: Evaluation of Time-Series Model Performance

Scrub typhus (ST) is expanding its geographical distribution in China and in many regions worldwide raising significant public health concerns. Accurate ST time-series modeling including uncovering the role of environmental determinants is of great importance to guide disease control purposes. This study evaluated the performance of three competing time-series modeling approaches at forecasting ST cases during 2012–2020 in eight high-risk counties in China. We evaluated the performance of a seasonal autoregressive-integrated moving average (SARIMA) model, a SARIMA model with exogenous variables (SARIMAX), and the long–short term memory (LSTM) model to depict temporal variations in ST cases. In our investigation, we considered eight environmental variables known to be associated with ST landscape epidemiology, including the normalized difference vegetation index (NDVI), temperature, precipitation, atmospheric pressure, sunshine duration, relative humidity, wind speed, and multivariate El Niño/Southern Oscillation index (MEI). The first 8-year data and the last year data were used to fit the models and forecast ST cases, respectively. Our results showed that the inclusion of exogenous variables in the SARIMAX model generally outperformed the SARIMA model. Our results also indicate that the role of exogenous variables with various temporal lags varies between counties, suggesting that ST cases are temporally non-stationary. In conclusion, our study demonstrates that the approach to forecast ST cases needed to take into consideration local conditions in that time-series model performance differed between high-risk areas under investigation. Furthermore, the introduction of time-series models, especially LSTM, has enriched the ability of local public health authorities in ST high-risk areas to anticipate and respond to ST outbreaks, such as setting up an early warning system and forecasting ST precisely.

Emergence of “urban scrub typhus” during Monsoon season in an urban pocket and biodiversity hotspot of New Delhi, India

Introduction: Scrub typhus is an endemic disease transmitted within the “epidemiological tetrad” of rains, rodents, chigger mites, and scrub vegetation prevalent in “Tsutsugamushi Asia-Pacific triangle,” predisposing one billion population at risk and annual incidence of one million. Scrub typhus is difficult to differentiate clinically from coendemic vector-borne acute undifferentiated febrile illness (AUFI). Untreated scrub typhus may cause disseminated vasculitis, serositis, and hemophagocytic syndrome. Outbreaks of scrub typhus have been reported from Thailand, China, Korea, and rural India. Transmission of scrub typhus in urban areas is relatively rare. Three consequent outbreaks in a urban pocket in New Delhi, India, highlight emergence of urban scrub typhus. Materials and Methods: A cross-sectional, clinicoepidemiological, ambispective outcome surveillance study was conducted among all clinicodemographically homogenous patients presenting with AUFI during 2016–2018. Clinically suspected or intuitively investigated scrub typhus was screened by IgM/IgG immunochromatography and confirmed through IgM enzyme-linked immunosorbent assay and real-time polymerase chain reaction. Spatial, temporal, and vector surveillance through epidemiological mapping, line listing, and mite surveillance was done. Results: Scrub typhus outbreaks affected 161 patients during 2016–2018. Mean age was 31.77 ± 17 years. Most common clinical presentation was fever with headache. Eschar was present in 46.88% patients commonly on abdomen, chest, perineum, and extremities. Coinfections and comorbidities were seen in 3.75% and 14.37% patients, respectively. Seventy percent and 14.8% patients were managed in acute care and intensive care. Mean hospital stay was 8.96 ± 3.86 days. Doxycycline and doxycycline-azithromycin combination were given in 92.5% and 7.5% patients, respectively. All-cause mortality was 6.25%. 126/160 (78.75%) patients were geospatially distributed from urban landscape depicted in epidemiological maps. Temporal-seasonal distribution revealed bell-shaped curve from May to November. Mite carriage was seen in 16% rodents. Conclusion: Urban scrub typhus is emerging in microhabitats fulfilling the epidemiological tetrad and chigger mites undergoing transovarian transmission. Geospatial and temporal mapping are required in urban neighborhoods for risk stratification, outbreak management, vector control, and community education. A high index of suspicion in AUFI and early initiation of doxycycline therapy are required.

An outbreak investigation of scrub typhus in Nepal: confirmation of local transmission

BackgroundScrub typhus is a largely ignored tropical disease and a leading cause of undifferentiated febrile illness in the areas of tsutsugamushi triangle caused by Orientia tsutsugamushi. It is frequently diagnosed in South Asian countries, although clear epidemiological information is not available from Nepal. After the 2015 earthquake in Nepal, a sudden upsurge in scrub typhus cases was reported. The objective of this study was to investigate epidemiology of scrub typhus and its causative agents in humans, animals, and chigger mites to understand the ongoing transmission ecology.MethodsScrub typhus cases with confirmed diagnosis throughout the country were included in the analysis. Studies were concentrated in the Chitwan district, the site of a major outbreak in 2016. Additional nation-wide data from 2015 to 2017 available from the government database included to analyse the disease distribution by geographical mapping.ResultsFrom 2015 to 2017, 1239 scrub typhus cases were confirmed with the largest outbreak occurring in 2016 with 831 (67.1%) cases. The case fatality rate was 5.7% in 2015 which declined to 1.1% in 2017. A nationwide outbreak of scrub typhus was declared as the cases were detected in 52 out of the 75 districts of Nepal. Seasonal trend was observed with a peak during August and September. In addition to the human cases, the presence of O. tsutsugamushi was also confirmed in animals (rodents) and chigger mites (Leptotrombidium imphalum) from the outbreak areas of southern Nepal.ConclusionThe detection of O. tsutsugamushi in humans, animals, and chigger mites from outbreak locations and wide-spread reports of scrub typhus throughout the country consecutively for 3 years confirms the ongoing transmission of O. tsutsugamushi with a firmly established ecology in Nepal. The country’s health system needs to be strengthened for systematic surveillance, early outbreak detection, and immediate actions including treatment and preventive measures.

Outbreak of scrub typhus in Manipur experience at a tertiary care hospital

Outbreak of scrub typhus in Manipur experience at a tertiary care hospital

Clinical and biochemical profile of scrub typhus patients at a tertiary care hospital in Northern India.

Background:Scrub typhus is a neglected rickettsial disease in India. Every year, we are facing outbreaks of Scrub typhus after Monsoon season. Patients present with a wide clinical spectrum ranging from pyrexia of unknown origin to multiple organ dysfunction. Some of these clinical features overlap with presentation of other tropical infections prevalent in Indian subcontinent, which leads to diagnostic dilemma and delay in diagnosis. Hence, we planned this study to know the demographic, clinical and biochemical profile of scrub typhus patients.Methods:This was an observational study conducted in department of Medicine, King George's Medical University Lucknow, India a leading tertiary care hospital of Northern India. All scrub typhus patients were evaluated by detailed history, examination and laboratory tests.Results:We enrolled 52 patients in our study. The mean age of the patients was 35.17 ± 16.90 years with majority (82.7%) of patients from rural background. All the patients had fever with an average duration of 9.6 ± 2 days. Most of the patients developed hepatitis (69.2%) followed by acute encephalitis syndrome (47%), acute kidney injury (23.1%) and acute respiratory failure (19.2%). Eschar was found in 11 patients (21.2%).Conclusion:Scrub typhus is often misdiagnosed or diagnosed late due to its wide clinical spectrum overlapping with clinical presentation of other commonly prevalent tropical diseases. One should always consider the differential diagnosis of scrub typhus while evaluating a young febrile patient of rural background, with features of single or multiple organ dysfunction and laboratory findings of leucocytosis, thrombocytopenia and elevation of transaminases.

Neurological manifestations in scrub typhus from a case series in Southern India

Scrub typhus is an acute febrile illness caused by Orientia tsutsugamashi. CNS is the most crucial target in other rickettsial diseases and historically, the neurological disease burden was considered low in scrub typhus. However, there is growing evidence in literature that O. tsutsugamushi does invade the CSF and CNS invasion may be seen in 2–5 % cases of tsutsugamushi disease. O. tsutsugamushi parasitises endothelial cells both in the periphery as well as in the brain. The disease is characterized by focal or disseminated vasculitis and perivasculitis. Scrub typhus has protean manifestations. CNS involvement is rare but it should be considered as an important differential in the setting of known areas of scrub typhus outbreak. Meningoencephalitis with or without focal neurological deficits is the commonest clinical picture. However, the neurological manifestations can be highly variable. In our case series out of 81 patients who were diagnosed with scrub typhus, only 5 patients had neurological manifestations. All patients presented with altered sensorium. GCS was decreased in all patients. It was <10 in 60% cases. Neck rigidity and signs of meningeal irritation was present in 80% cases. There was no sign of papilloedema, cranial nerve involvement, focal neurological deficits. 2 of the patients had seizure which was GTCS in semiology. CSF in all cases showed lymphocytic predominance (between 150 and 400 cells/ mm3) with high protein and low to normal CSF sugar levels. NCCT brain was normal. MRI brain showed meningeal enhancement in 60% cases. Additionally, hyperintense signal on T2 was observed in 60% cases. Confirmation of the case requires serological evidence. CSF and neuroimaging picture are not pathognomonic. In the setting of acute fever, headache along with eschar or macular rash, scrub typhus must be ruled as a cause of neurological manifestations, such as altered sensorium, and seizure.

Epidemiology and clinical profile of scrub typhus outbreak in a tertiary care centre of central India

Background: Scrub typhus is the most common rickettsial infection in the Indian subcontinent with the manifestation ranging from mild symptoms to serious disease with or complication or death. The objective of this study was to study epidemiology and clinical profile of scrub typhus outbreak in a tertiary care centre of central India.Methods: Present study is a record based retrospective study enrolling 173 confirmed positive cases with ELISA test during the period from 1st August to 31st December 2018.Results: Maximum number of the cases 94 (54.3%) had occurred in September 2019. Majority of the female 94(54.3%) were Ig M positive for scrub typhus. Maximum cases 134 (77.5%) were from rural area. Most common symptoms were fever 170 (98.3%), followed by fever with chills 65 (37.6%), breathlessness 49 (28.3%), cough 35 (20.2%), and 28 (16.2%) each with altered sensorium and headache. Mortality was recorded in 30 (173%) and amongst them 10 (34.5%) and 4 (13.8%) cases had ARDS and septicaemia as complication respectively.Conclusions: This study shows that majority of the cases occurred in the month of September 2018 with female preponderance. Most of the residence were from rural areas with common presenting symptoms as fever or fever with chills followed by breathlessness, cough and altered sensorium and headache.